In the minutes after the Marathon bombings, phones began to ring and buzz as people checked on family members, friends, and distant relations in Boston. R U OK?, they texted. What happened, they asked.

Researchers at Northeastern University are asking residents and visitors who used their cellphones to keep in touch with their social network after the bombings to download a smartphone app to help them understand how, exactly, we communicated in the aftermath of the tragedy. Did we call the people we are in touch with most frequently, or were we flooded with voicemails and messages from people we haven’t spoken to in weeks or years?

When people open the app, they will be asked to answer a survey and provide information from their cellphones’ text and call logs. Researchers also plan to look at how information rippled outward on social media sites such as Facebook and Twitter.

“From an emergency response point of view, you want to know how information disseminates among the population,” said David Lazer, a Northeastern political science professor who is heading up the research. From a more sociological perspective, communication patterns may reveal something about the texture of human life.

“The most important resource people have immediately in the aftermath of an emergency are the networks,” Lazer said. “So, to understand how people utilize those networks and what kind of relationships you have with the people you call — to what ­extent do we still rely on our kin network in this modern” day.

Already, the researchers have created an “emotional Tweet map,” a data visualization showing Twitter activity across the Boston area, through tracking messages that expressed fear. The entire city began to blaze red with activity shortly after the bombs went off.

After Hurricane Sandy, the researchers designed a similar app that would allow them to examine communication patterns as a natural disaster unfolded. Now, they are hoping to collect a similar but larger dataset that will help reveal how the reaction to the deadly blasts rippled through our social networks.

The data will be anonymized, and researchers will not have access to the contents of messages or the identities of people. For every person who contributes their data, the researchers are donating $3 to the One Fund that has been established for bombing victims.